Nuclear Reactions
Notes:
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-
You need to write down everything in red for
your notes
If it is not in red, it is interesting to know, but
not required
Take notes in CORNELL style – Remember
to write the questions and summary
BY THE WAY, THAT IS YOUR HOMEWORK
5 questions and a 3 sentence summary
Uses For Nuclear Reactions
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Nuclear weapons
Uses For Nuclear Reactions
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Nuclear Weapons
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Power Plants
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Radiation therapy for cancer patients
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Radioactive dating using carbon 14
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Used to find how old archeological artifacts are
Medical tests
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PET scans
Types of Radiation - Review
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Alpha decay
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Beta decay
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Strong ionization – grabs electrons
Stopped by a piece of paper
Can penetrate 1 cm into skin
Gamma decay
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High energy – like X-rays
Most penetrating – Can go through
most materials easily
Most damaging radiation
Nuclear Reactions
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Two types of Nuclear Reactions
 Fission – splitting atoms apart
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Atomic bomb
Power plants
Fusion – fusing atoms together
 The sun
 Hydrogen bomb
Nuclear Fission
1. Neutron hits a uranium or plutonium atom
2. The nucleus splits into 2 smaller atoms + free
neutrons
3. Each split releases energy in the form of gamma
radiation
4. The free neutrons fly away to hit another atom –
causing a CHAIN REACTION
Nuclear Fission – Chain Reaction
Critical mass – The amount of material
needed for a chain reaction to happen
Want to see a chain reaction?
Nuclear Fusion
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Deuterium (21H) is combined with Tritium (31H) to
make Helium
Atoms must be smashed together with extreme
force to stick together
Only happens at millions of degrees – As hot as
the Sun
There is no nuclear waste in a fusion reaction
Why are nuclear reactions
such a big deal?
The Answer:
E=
2
mc
(energy = mass x speed of light squared)
This famous equation was
Are
you ready
knowEinstein.
what Einstein
discovered
by to
Albert
knew?
E = mc 2
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Energy = mass times the speed of light squared
Einstein discovered that mass and energy are
related by this equation
Only nuclear fission or fusion release close to this
much energy
So….for 1 gram (speed of light is 299,792,458 m/s)
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Energy = .001kg x (2.99 x 108 m/s)2 =
89,000,000,000,000 Joules
Benefits of Nuclear Reactions
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Efficient Energy Source – A lot of energy for a
little fuel
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Fossil fuels are being used up
Burning fuel is causing environmental pollution
Medical uses for radiation
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Treating cancer
Imaging
Dangers of Nuclear Reactions
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Nuclear Meltdown
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Chernobyl (1986) – world’s worst nuclear accident
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Located in Ukraine – former Soviet Union
31 people killed
Surrounding area contaminated for next 50 years
Dangers of Nuclear Reactions
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Effects of Radiation on Humans
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Radiation Sickness
Cell damage
Mutations
Increased Risk of Cancer
REMEMBER: You are exposed to radiation every
day! Your cells will heal themselves from small
amounts of radiation.
Dangers of Nuclear Reactions:
Effects of Radiation
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Hand of Scientist at Los Alamos – 9 days after
exposure
Public Service Message from Ms.
Kuhl.
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If you don’t want to get mutated…eat
your fruits and vegetables
Eating fruits and vegetables seems to
protect you from cell damage
Hiroshima and Nagasaki survivors
who ate vegetables had less chance
of getting cancer even after being
exposed to large amounts of radiation
French fries don’t count
Dangers of Nuclear Reactions
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Environmental Risk
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Nuclear waste created by nuclear fission is still
radioactive
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Dispose by burying underground
Can remain radioactive for hundreds of years
Soil and Water contamination
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Affects plants and animals
Food and water become unsafe
The Future?
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Nuclear power
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Some countries generate 50% of their power using
nuclear fission
Does not cause air pollution – global warming
The dream of fusion
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Uses simple materials – Uses water!
No nuclear waste
But you need millions of degrees to do it
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Some scientists thought they had discovered cold
fusion
They were wrong 